Telephone system.



EATE'ETEE AUG. 25, 1908.

I A. H. WEISS.

TELEPHONE sYsTEM.

APPLICATION FILED DEC 13 1902 UNITED STATES PATENT OFFICE ALFRED II.WEISS, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCHBOARD AND SUPPLYCOMPANY, OF CHICAGO, ILLINOIS A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Aug. 25, 1908.

Application filed December 13,1902. Serial No. 135,027.

T 0 all whom it may concern:

Be it known that I, ALFRED I I. News, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented new and useful Improvements in Telephone Systems, of which thefollowing is a specification.

My invention relates to telephone systems of the common battery type andin which only two wires extending throughout the switchboard arerequired for conversation and for the operation of the various cut-offand supervisory relays associated with the lines.

It has particular reference to means whereby in such two wire commonbattery multiple switchboard systems it is not necessary to providenormally open contacts in the line circuits.

Other objects are the provision of a system of the type mentioned thatis simple and convenient to install and one that is eflicient anddurable in operation.

In the accompanying drawing in which the same reference charactersindicate like parts throughout the several views Figure l is a diagramof the system embodying my improvement; Fig. 2 is a diagram of amodification in the line circuit; Fig. 3 is a diagram of a differentarrangement of the line lamp, and Fig. 4 is a diagrammatic view of stilla different arrangement.

Referring to Fig. 1, L and L indicate subscribers lines extending in twolimbs 2 and 3 from their respective substations to the central oflice.Upon the line L a single station A is shown at which are provided a callhell 4 and condenser 5, preferably in a permanent bridge of the lineconductors, while a receiver 6 and a transmitter 7 are connected in anormally open bridge by the switchhook 8. At the central office the lineis fitted with an answering jack J and any suitable number of multiplejacks such as J 2 and J having their tip and sleeve contacts permanentlyconnected and forming extensions of the respective line conductors. Theline conductor 2 includes the winding of the line relay R as well as thenormal contact of the cut-off relay R and is thence connected by a mainlead 9 with the live pole of a central and common source B of steadycurrent. The relay R controls through its normally open contacts thecircuit of the line signal S which is preferably in the form of a smallincandescent lamp. The sleeve line conductor 3 permanently includes thehelix of the cutoff relay R and has a branch to ground, in addition,which is normally closed through spring 10 of relay R and springs 11 and12 of relay R, the latter spring being adapted to make connection withthe branch conductor 13 before it is separated from the spring 11 whenthe relay It is actuated. The line L is in this instance shown as apartyline or as a poly-station line, the arrangement being substantiallythe same at each sub-station as at the station A except that the bellsare grounded from the different line conductors.

The operators outfit includes a cord circuit'having an answering plug Pand a calling plug P each provided with tip and sleeve contacts adaptedto register with the similar contacts of, the connecting jacks. The tipcontacts of the plugs are joined by the strands t and t of the cordcircuit and the interposed condenser 0, while the sleeve contacts ofsaid plugs are likewise joined by the flexible strands s and s and theinterposed condenser 0 The battery B is bridged across the answering endof the cord circuit and includes upon one side the su ervisory relay 1"and upon the other side t e sleeve supervisory relay 1, the formercontrolling through its normally closed contacts and the latter throughits normally open contacts the local circuit of the supervisory signal Sassociated with the plug P and preferably charged from the battery B.The battery B is similarly connected across the calling end of the cordcircuit and is provided upon one side with'the tip su ervisory relay rand upon the other with t e sleeve supervisory relay T which togethercontrol the. super visory signal S associated with the plug P The tipstrand of the cord circuit is severed at spring 14 of relay r by whichits forward portion is normally connected through a common conductor15-with the high impedance and high resistance test relay T the otherpole of which is grounded. This relay is preferably common to the cordcircuits of each operators position and serves through its normally opencontacts to complete a path for current through the operators inductioncoil to thereby cause a click in her receiver. The.operators transmitter16 is connected in a conductor 17 which is joined to the common wire 9The primary helix the answering plug of the cord circuit thereof theoperators induction coil 18 and the condenser c are in a shunt of thetransmitter 16. The operators receiver 19, the secondary of herinduction coil and the condenser s are adapted to be bridged across thecalling end of the cord circuit by the springs 19 of any suitablelistening key. The calling generator 20 is adapted by the operation ofringing springs 21 to deliver alternating current to the tip side of theline, while connecting the sleeve side through resistance coil 22 withthe omnibus bar 9. The same generator by the depression of springs 23 ofthe ringing key is arranged to deliver pulsating current, preferably ofnegative polarity with the sleeve line conductor and at the same timegrounding the tip conductor.

Upon taking up the receiver at the station A the line conductors areclosed together thus permitting current from the battery B to flow overthe branch 9 and the tip conductor 2, through the sub-stationinstruments and back to the central office over the line conductor 3through spring 10 of relay R and springs 11 and 12 of relay R to ground.The line relay R responds to this current closing through its normallyopen contacts the circuit of the lamp S and also connects a lockingcircuit for itself through the branch. 13 and spring 12 to ground. Thislocking circuit is completed before the spring 11 is separated from 12whereby the line relay is maintained actuated, and the ground connectionfrom the sleeve conductor is severed. Upon noticing the signal theoperator inserts by completing a path for current from the battery Bover the sleeve strand 8 through the sleeve conductors of the jacks, andthrough the branch containing the cut-oil relay R which is actuated toopen the circuit of the line relay thus rendering the same and the linesignal inoperative and opening at a different point the said groundbranch At the same time the sleeve supervisory relay r is energized toclose the circuit of supervisory lamp S which, however, is preventedfrom operating at this time by the actuation of relay which is in thepath of current over the line conductor to the substation.

The wanted line is tested in the usual in anner by touching the tip of acalling plug to a test ring thereof. Under normal conditions the testrings are connected to ground and since the tip of the plug is likewiseconnected the testing of an idle line gives no click, but

if the line is busy the test rings are connect-- ed. through the sleevestrand of the cord eir cuit with the live pole of a battery whereby theyare raised to a potential above earth, and the application of a testingplug thereto results in a flow of current through the test relay 7'causing it to close a path for current through the induction coil in theoperators outfit. This relay is preferably of high resistance and. highimpedance to prevent a large or sudden change of current upon the testedlines. It will be obvious that the relay may be replaced by a thirdwinding in the operators induction coil or in other ways.

Upon finding the line idle the calling plug is inserted in one of themultiple acks of the line whereupon the line relay R is given an impulseby current to ground over the tip conductor of the plug. Upon theactuation of this relay the short circuit is removed from the coil ofthe cut-oil relay R and the latter is immediately operated by currentover the sleeve conductor of the cord. the line signal S is therebyclosed and opened again so quickly that the signal will not bedisplayed. The ringing key is now operated and the depression of springs21 connects the generator with the tip side of the line and operates thebell at station D, while the sleeve connection with the live pole ofbattery B is maintained through the coil 22 to main tain the cut-offrelay actuated during ringing and to provide a low resistance path for Lringing current in case of the response of the subscriber duringringing. The operation of springs 23 of the ringing key connects thesaid generator with the sleeve line conductor and thereby operates thebell at the station C. The pulsating current serves to maintain thecut-oil relay of the called line in actuated condition while the tipspring closes a low resistance path to ground for the return of theringing current. It will be apparent that either set of springs may beemployed for calling single subscribers located upon metallic lines.

Before the response of the called sub scriber the supervisory relay roperates to The circuit of close a local circuit of the supervisory lampS which is lighted, and remains in this condition until the subscriberresponds. At the same time the test relay is disconnected and the tipstrand 25 completed through the spring 14 for conversational purposes.The response of the called subscriber permits a flow of current from thebattery B over the metallic line thus operating supervisory relay 1 toextinguish lamp S During conversation the two batteries are connectedwith their respective lines to furnish current for transmission and. forthe operation of the various relays associated therewith. Thesubscribers set is intended to typify any of the usual or desired typeof common battery outfits. The cut-oil relays R are preferably in theneighborhood. of 500 ohms resistance while the line relays and thesupervisory relays may be of 100 ohms resistance. At the termination ofthe conversation the return of the receivers to the hooks opens the linecircuits to steady current thereby de'e'nergizing supervisory relays rand r and permitting the two supervisory lamps to operate. Upon noticingthese the operator takes down the connection and restores all parts tonormal condition.

Fig. 2 shows a modification in which the additional contact upon theline relay is dis pensed with by extending the local circuit of the lampto a second forward contact 25 of line spring 12. Or the said line lampmay obviously have its circuit otherwise connected to produce the sameresult without departing from the spirit of my invention. The operationof this form of the invention is manifest.

Fig. 3 shows a slightly different modification in which the lamp S isplaced in the ground branch from the spring 12, it being merelynecessaryto use a lamp that will light through the resistance of the line relayB.

Fig. 4 shows the lamp located in the branch 13, the operation beingotherwise the same as before described.

'Other modifications, it is apparent, may

. be made without departing from the principle or scope vof theinvention for which reason I do not wish to be limited in all respectsand in all claims to this special form shown.

I claim:

1. The combination with a telephone line extending in two limbs to thecentral station, of a signal circuit associated therewith, a relaywinding permanently connected between one of said limbs and a thirdconductor and out of the path of calling current from the subscribersstation, a contact in said signal circuit controlled by said winding, asource of current at the central station adapted to be connected betweensaid third conductor and the limb with which said relay winding isconnected and to send current through said relay winding over a circuitincluding a portion of the talking circuit of the telephone line, saidsource also serving to furnish current to the subscribers station fortalking,

substantially as described.

2. The combination with a telephone line extending in two permanentlimbs direct to the line contacts in the switchboard at the centralstation, of a relay winding connected between one of said limbs and athird conductor and out of the path of calling current from thesubscribers station, a contact controlled by said winding, a signalcircuit controlled by said contact, a cord connector terminating in aconnecting plug, a charging source of electricity at the central stationconnected between said third conductor and one strand of the cordconnector and ada ted to be included in the metallic circuit 0' the lineto furnish current to the substation of the line for talking, and tosend current through said relay winding over a circuit including one ofthe main terminals of the connecting plug to deprive said signal circuitof current, a portion of the cord circuit, and a line contact of thetelephone line, substantially as described.

3. The combination with a telephone line extending in two continuouslimbs to the springjacks at the central station, of a signal controllingelectro-magnet normally connected with the line, a relay for opening thecircuit of said electro-magnet and having its winding permanentlyconnected with one of said limbs out of the path of calling current fromthe subscribers station, a source of current at the central ofliceadapted to be included in the metallic circuit of said line to furnishcurrent to the subscribers station for talking, and means for closingcircuit from said. source through said relay winding over a portion ofthe talking circuit of the telephone line when connection is made withthe line, substantially as described.

4. The combination with a telephone line extending in two limbs to thecentral station, of a connection terminal having its contactspermanently connected with the line, a line signal, a relay forrendering said signal inoperative and permanently connected with theline and out of the path of the calling current from the subscribersstation, a source of current at the central oliice adapted to beincluded in the metallic circuit of said line to furnish current fortalking to the substation, and means for closing circuit through saidrelay over a portion of the talking circuit when connection is made withthe line, substantially as described.

5. In a telephone system, the combination with a telephone lineextending in two continuous limbs to the spring acks at the centraloffice, of a line signal therefor, means for operating the same bycalling current sent over the line from the subscribers station, acut-off relay for the line permanently connected therewith and out ofthe path of calling current, said relay being adapted when actuated torestore the line signal to normal condition, and means for energizingsaid relay over a portion of the talking circuit when a connection isestablished with the line, substantially as described.

6. In a telephone system, the combination with a telephone line havingits limbs extending continuously throughout the switchboard, of a linesignal therefor, a line relay to actuate said signal when a callingcurrent is sent over the line by the subscriber, a cut-off relaypermanently connected with the line out of the path of calling currentand adapted when operated to open the circuit of said line relay, andmeans for energizing the cutoff relay by current flowing over a portionof the talking circuit when a connection is es tablished with the line,substantially as described.

7. In a telephone system, the combination with a telephone lineextending in two continuous limbs to the spring jacks at the centraloffice, of a source of current with which said limbs are connected atthe central oflice, a line relay or electro-magnetic signaling deviceconnected with one of said limbs, a cutofl relay permanently connectedbetween one of said limbs and a third conductor, said cutoff relay beingout of the path of the current in the line when the subscriber iscalling the central oflice, and adapted to be actuated when a connectionis established. by current over a portion of the talking circuit and thethird conductor, substantially as described.

8. In a telephone system, the combination with a telephone lineextending in two continuous limbs to the spring acks at the centraloffice and included in the talking circuit,

of a central source of current with which the limbs of said lines arenormally connected, a line relay connected with one of said limbs, acut-off relay legged to ground from the other limb out of the path ofcurrent when the subscriber is calling the central office and ada tedwhen actuated to render said line re ay inoperative, and means foractuating said cut-oil relay by current over a portion of the talkingcircuit and ground when a connection is established with the line,substantially as described.

9. In a telephone system, the combination with the telephone line, of asource of current with which the limbs thereof connect, a line relay inone of the limbs, said relay serving when actuated to open the otherlimb, a cutoff relay connected with the latter limb beyond the point ofopening the same, and means for actuating the latter relay over aportion of the talking circuit when a connec tion is established withthe line, substantially as described.

10. In a telephone system, the combination with a telephone lineprovided with spring jacks upon the switchboard at the central office,the limbs of said line being continuous to the contacts of said jacks, aline signal for the line at the central ofiice, a cutoff deviceassociated with the line but out of the path of current therein when thesubscriber is calling the central office, said cutoff device beingoperated by current over a path including a portion of the talkingcircuit when a connection for conversation exists with the line tothereby restore the line signal to normal condition, substantially asdescribed.

Signed by me at Chicago, county of Cook, State of Illinois, this 10thday of December ALFRED H. WEISS. Witnesses:

GAZELLE BEDER, ROBERT LEwIs Arms.

